Neuromuscular disuse and atrophy: {\it In vivo\/} magnetic resonance studies of intramuscular lipid metabolism and fluid shift changes

We postulated that neuromuscular disuse results in deleteriously affected tissue-vascular fluid exchange processes and subsequently damages the important oxidative bioenergetic process of intramuscular lipid metabolism. The in-depth research reported in the literature is somewhat limited by the ex vivo nature and sporadic time-course characterization of disuse atrophy and recovery. Thus, an in vivo controlled, localized animal model of disuse atrophy was developed in one of the hindlimbs of laboratory rabbits (employing surgically implanted tetrodotoxin (TTX)-filled mini-osmotic pump-sciatic nerve superfusion system) and tested repeatedly with magnetic resonance (MR) throughout the 2-week period of temporarily induced disuse and during the recovery period (following explantation of the TTX-filled pump) for a period of 3 weeks. Controls consisted of saline/"sham"-implanted rabbit hindlimbs. The validity of this model was established with repeated electrophysiologic nerve conduction testing using a clinically appropriate protocol and percutaneously inserted small needle stimulating and recording electrodes. Evoked responses recorded from proximal (P) and distal (D) sites to the sciatic nerve cuff in the TTX-implanted group revealed significantly decreased (p $<$ 0.001) proximal-to-distal (P/D) amplitude ratios (as much as 50-70% below Baseline/pre-implanted and sham-implanted group values) and significantly increased (p $<$ 0.01) differential latency (PL-DL) values (as much as 1.5 times the pre- and sham-implanted groups). By Day 21 of recovery, observed P/D and PL-DL levels matched Baseline/sham-implemented levels. MRI-determined cross-sectional area (CSA) values of Baseline/pre-implanted, sham- or TTX-implanted, and recovering/explanted and the corresponding contralateral hindlimb tibialis anterior (TA) muscles normalized to tibial bone (TB) CSA (in TA/TB ratios) revealed that there was a significant decline (indicative of atrophic response) from pre- and sham-implanted controls by as much as 20% (p $<$ 0.01) at Day 7 and 50-55% (p $<$ 0.001) at Day 13 of TTX-implantation. In the non-implanted contralaterals, a significant increase (indicative of hypertrophic response) by as much as 10% (p $<$ 0.025) at Day 7 and 27% (p $<$ 0.001) at Day 13 + TTX was found. The induced atrophic/hypertrophic TA muscles were observed to be fully recovered by Day 21 post-explantation as evidenced by image TA/TB ratios. End-point biopsy results from a small group of rabbits revealed comprehensive atrophy of both Type I and Type II fibers, although the heterogeneity of the response supports the use of image-guided, volume-localized proton magnetic resonance spectroscopy (MRS) to noninvasively assess tissue-level metabolic changes. MRS-determined results of a 0.25cc volume of tissue within implanted limb TA muscles under resting/pre-ischemic, ischemic-stressed, and post-ischemic conditions at timepoints during and following disuse atrophy/recovery revealed significantly increased intramuscular spectral lipid levels, as much as 2-3 times (p $<$ 0.01) the Baseline/pre-implanted values at Day 7 and 6-7 times (p $<$ 0.001) at Day 13 + TTX, which approached normal levels (compared to pre- and sham-implanted groups) by Day 21 of post-explanation recovery. (Abstract shortened by UMI.) ^

Expression of neuromuscular junction messenger RNAs and protein in aged rats

The loss of skeletal muscle mass is believed to be the dominant reason for reduced strength in aging humans. The purpose of this investigation was to gain some information as to why skeletal muscles lose mass as we age. Since nervous system innervation is essential for skeletal muscle fiber viability, incomplete regional reinnervation during normal synaptic junction turnover has been hypothesized to result in selective muscle fiber loss. Examined here was the age-related association in skeletal muscle between atrophy and the expression of mRNAs encoding the γ- and ϵ-subunits of the nicotinic acetylcholine receptor, myogenin, and muscle specific receptor kinase (MuSK). Gastrocnemius and biceps brachii muscles were collected from young (2 month), adult (18 month), and old (31 month) Fischer 344 cross brown Norway F 1 male rats. In the gastrocnemius, muscles of old vs. young and adult rats, lower muscle mass was accompanied by significantly elevated acetylcholine receptor γ-subunit, myogenin, and MuSK mRNA levels. In contrast, the biceps brachii muscle in the same animals exhibited neither atrophy nor a change in acetylcholine receptor γ-subunit, myogenin, or MuSK mRNA levels. Expression of the acetylcholine receptor ϵ-subunit mRNA did not change with age in either gastrocnemius or biceps brachii muscles. Since acetylcholine receptor γ-subunit, myogenin, and MuSK mRNA levels are upregulated in surgically denervated skeletal muscles of young rats while expression of the acetylcholine receptor ϵ-subunit does not change, the findings of the current investigation suggest that a select fiber population within atrophied skeletal muscles of old rats may be in a denervated-like state. I speculate that increases in γ-subunit, myogenin, and MuSK mRNA levels in atrophied muscles of old rats are compensatory responses to nerve terminal retraction. Indeed, a prolongation of denervation in these muscle fibers would subsequently result in their atrophy and death, ultimately leading to a decline in the number of force generating elements present in the muscle. ^

The craniosacral progression of muscle development influences the emergence of neuromuscular junction alterations in a severe murine model for spinal muscular atrophy.

AIMS As 4-day-old mice of the severe spinal muscular atrophy (SMA) model (dying at 5-8 days) display pronounced neuromuscular changes in the diaphragm but not the soleus muscle, we wanted to gain more insight into the relationship between muscle development and the emergence of pathological changes and additionally to analyse intercostal muscles which are affected in human SMA. METHODS Structures of muscle fibres and neuromuscular junctions (NMJs) of the diaphragm, intercostal and calf muscles of prenatal (E21) and postnatal (P0 and P4) healthy and SMA mice were analysed by light and transmission electron microscopy. NMJ innervation was studied by whole mount immunofluorescence in diaphragms of P4 mice. RESULTS During this period, the investigated muscles still show a significant neck-to-tail developmental gradient. The diaphragm and calf muscles are most and least advanced, respectively, with respect to muscle fibre fusion and differentiation. The number and depth of subsynaptic folds increases, and perisynaptic Schwann cells (PSCs) acquire a basal lamina on their outer surface. Subsynaptic folds are connected to an extensive network of tubules and beaded caveolae, reminiscent of the T system in adult muscle. Interestingly, intercostal muscles from P4 SMA mice show weaker pathological involvement (that is, vacuolization of PSCs and perineurial cells) than those previously described by us for the diaphragm, whereas calf muscles show no pathological changes. CONCLUSION SMA-related alterations appear to occur only when the muscles have reached a certain developmental maturity. Moreover, glial cells, in particular PSCs, play an important role in SMA pathogenesis.

Outbreak investigation identifies a single Listeria monocytogenes strain in sheep with different clinical manifestations, soil and water.

Listeria (L.) monocytogenes causes orally acquired infections and is of major importance in ruminants. Little is known about L. monocytogenes transmission between farm environment and ruminants. In order to determine potential sources of infection, we investigated the distribution of L. monocytogenes genetic subtypes in a sheep farm during a listeriosis outbreak by applying four subtyping methods (MALDI-TOF-MS, MLST, MLVA and PFGE). L. monocytogenes was isolated from a lamb with septicemia and from the brainstem of three sheep with encephalitis. Samples from the farm environment were screened for the presence of L. monocytogenes during the listeriosis outbreak, four weeks and eight months after. L. monocytogenes was found only in soil and water tank swabs during the outbreak. Four weeks later, following thorough cleaning of the barn, as well as eight months later, L. monocytogenes was absent in environmental samples. All environmental and clinical L. monocytogenes isolates were found to be the same strain. Our results show that the outbreak involving two different clinical syndromes was caused by a single L. monocytogenes strain and that soil and water tanks were potential infection sources during this outbreak. However, silage cannot be completely ruled out as the bales fed prior to the outbreak were not available for analysis. Faeces samples were negative, suggesting that sheep did not act as amplification hosts contributing to environmental contamination. In conclusion, farm management appears to be a crucial factor for the limitation of a listeriosis outbreak.

Chronological Order of Appearance of Extraintestinal Manifestations Relative to the Time of IBD Diagnosis in the Swiss Inflammatory Bowel Disease Cohort.

BACKGROUND Data evaluating the chronological order of appearance of extraintestinal manifestations (EIMs) relative to the time of inflammatory bowel disease (IBD) diagnosis is currently lacking. We aimed to assess the type, frequency, and chronological order of appearance of EIMs in patients with IBD. METHODS Data from the Swiss Inflammatory Bowel Disease Cohort Study were analyzed. RESULTS The data on 1249 patients were analyzed (49.8% female, median age: 40 [interquartile range, 30-51 yr], 735 [58.8%] with Crohn's disease, 483 [38.7%] with ulcerative colitis, and 31 [2.5%] with indeterminate colitis). A total of 366 patients presented with EIMs (29.3%). Of those, 63.4% presented with 1, 26.5% with 2, 4.9% with 3, 2.5% with 4, and 2.7% with 5 EIMs during their lifetime. Patients presented with the following diseases as first EIMs: peripheral arthritis 70.0%, aphthous stomatitis 21.6%, axial arthropathy/ankylosing spondylitis 16.4%, uveitis 13.7%, erythema nodosum 12.6%, primary sclerosing cholangitis 6.6%, pyoderma gangrenosum 4.9%, and psoriasis 2.7%. In 25.8% of cases, patients presented with their first EIM before IBD was diagnosed (median time 5 mo before IBD diagnosis: range, 0-25 mo), and in 74.2% of cases, the first EIM manifested itself after IBD diagnosis (median: 92 mo; range, 29-183 mo). CONCLUSIONS In one quarter of patients with IBD, EIMs appeared before the time of IBD diagnosis. Occurrence of EIMs should prompt physicians to look for potential underlying IBD.

Incidence and predictors of cutaneous manifestations during the early course of systemic sclerosis: a 10-year longitudinal study from the EUSTAR database.

OBJECTIVES To longitudinally map the onset and identify risk factors for skin sclerosis and digital ulcers (DUs) in patients with systemic sclerosis (SSc) from an early time point after the onset of Raynaud's phenomenon (RP) in the European Scleroderma Trials and Research (EUSTAR) cohort. METHODS 695 patients with SSc with a baseline visit within 1 year after RP onset were followed in the prospective multinational EUSTAR database. During the 10-year observation period, cumulative probabilities of cutaneous lesions were assessed with the Kaplan-Meier method. Cox proportional hazards regression analysis was used to evaluate risk factors. RESULTS The median modified Rodnan skin score (mRSS) peaked 1 year after RP onset, and was 15 points. The 1-year probability to develop an mRSS ≥2 in at least one area of the arms and legs was 69% and 25%, respectively. Twenty-five per cent of patients developed diffuse cutaneous involvement in the first year after RP onset. This probability increased to 36% during the subsequent 2 years. Only 6% of patients developed diffuse cutaneous SSc thereafter. The probability to develop DUs increased to a maximum of 70% at the end of the 10-year observation. The main factors associated with diffuse cutaneous SSc were the presence of anti-RNA polymerase III autoantibodies, followed by antitopoisomerase autoantibodies and male sex. The main factor associated with incident DUs was the presence of antitopoisomerase autoantibodies. CONCLUSION Early after RP onset, cutaneous manifestations exhibit rapid kinetics in SSc. This should be accounted for in clinical trials aiming to prevent skin worsening.

Sickle cell disease: Its signs, symptoms and varied manifestations

Seventy-five sickle cell patients, age 3-36 years from Houston, Texas, participated in the research study to investigate sickle cell manifestations, conducted between November 1989 and August 1990. All the participants were blacks. There were 35 females and 39 males among the participants in this research study. One of the participants did not document the gender.^ The sickle cell history questionnaire was administered to the participants. Data collected from this study were statistically analyzed using frequencies, percentages, crosstabulations and chi-squares.^ Regular source of health care influences the time of diagnosis of sickle cell disease. Early diagnosis of sickle cell disease with proper care and management will reduce the morbidity and mortality rate of the disease.^ Fevers, bacterial infection, pneumoniae, anemiae, pains, ulcers and cardiovascular problems are common causes of hospitalizations. The average length of stay in the hospital on admission were higher among the sickle cell patients than their family members who themselves did not have sickle cell disease. ^

Average contents of chemical elements in different types of hydrothermal manifestations within 16°38'N hydrothermal field, MAR

An additional ore field in the central part of the MARhas been discovered. Together with previously discovered Logachev (14°45'N) and Ashadze (12°58'N) ore fields, the new ore field constitutes a cluster with preliminarily estimated total ore reserve of >10 Mt, which is comparable with large continental massive sulfide deposits.

Incidencia de la aplicación de un programa de fútbol en actividades que se basan en el incremento de las unidades motoras activas, utilizando como herramienta un adecuado entrenamiento de la fuerza de tipo neuromuscular en niños de 6-8 años

El presente trabajo es un macro ciclo de cinco meses que se realizó en la ACADEMIA DE FUTBOL ARNOLDO IGUARAN con niños en edades de los 6 a los 8 años pertenecientes al Municipio de La Villa de San Diego de Ubaté, Colombia; el objetivo principal fue determinar Incidencia de la aplicación de un programa de futbol, en actividades que se basan en el incremento de las unidades motoras activas, utilizando como herramienta un adecuado entrenamiento de la fuerza de tipo neuromuscular, haciendo énfasis en las acciones intermitentes y fundamental mente donde el niño este obligado a desarrollar fuerza y a entrenar con sobre cargas significativas

Incidencia de la aplicación de un programa de fútbol en actividades que se basan en el incremento de las unidades motoras activas, utilizando como herramienta un adecuado entrenamiento de la fuerza de tipo neuromuscular en niños de 6-8 años

El presente trabajo es un macro ciclo de cinco meses que se realizó en la ACADEMIA DE FUTBOL ARNOLDO IGUARAN con niños en edades de los 6 a los 8 años pertenecientes al Municipio de La Villa de San Diego de Ubaté, Colombia; el objetivo principal fue determinar Incidencia de la aplicación de un programa de futbol, en actividades que se basan en el incremento de las unidades motoras activas, utilizando como herramienta un adecuado entrenamiento de la fuerza de tipo neuromuscular, haciendo énfasis en las acciones intermitentes y fundamental mente donde el niño este obligado a desarrollar fuerza y a entrenar con sobre cargas significativas

Chemical composition of ferromanganese manifestations from the Sea of Okhotsk

New data on microstructures and mineral and chemical compositions of ferromanganese crusts sampled from the western slope of the Kuril Island Arc in the Sea of Okhotsk during cruises of R/V Vulkanolog are discussed. The study of the crusts using analytical electron microscopy methods revealed that their manganese phase is represented by vernadite, Fe-vernadite, todorokite, asbolane, and asbolane-buserite, while iron phase consists of hematite, hydrohematite, ferroxyhite, and magnetite. Lithic mineral assemblage includes apatite, quartz, epidote, and montmorillonite. According to chemical analysis most of the crusts contain significant part of volcanogenic and hydrothermal material. It is evident from elevated values of Mn/Fe and (Mn+Fe)/Ti ratios, low concentrations of some trace elements, and positive Eu anomaly.